The present invention relates to seating of the general type wherein an initially planar membrane is used as a seat bottom or seat back member to support a seat occupant. The membrane can be a woven or knitted fabric, or other material, and may be elastic or inelastic.
Aircraft passenger seats are required to be as lightweight as possible consistent with passenger safety and comfort. Passenger comfort depends to some extent on the time seated, which is itself a function of loading and unloading, taxiing, and flight time. Seats in relatively short haul, single seating class, commuter aircraft generally have lighter-weight seats with less cushioning. Often, the seat pan and backrest supports are formed of fabric membranes stretched across tubular frame members, and are initially planar, i.e., when not under load, they form a single two-dimensional plane across a span width. The membrane may be covered with a seat cushion. When under load, the combined deformation of the overlying seat cushion and the membrane provide an enlarged surface area of contact with and reduced pressure on the posterior (i.e., buttocks), thighs and back of the seat occupant.
Within the confines of required weight, g-loading, material, comfort and wear longevity criteria, determining the optimum characteristics of the seat bottom or seat back membrane in its “relaxed” state is desirable as a basis for providing a comfortable seat when the membrane is installed under tension and subjected to weight-induced loading.
Determining an optimum seat size and shape is particularly challenging within the required parameters of aircraft seat design. A wide variety of body shapes must be accommodated, in contrast to the ability of a chair purchaser to select and purchase a chair suited to the needs of individual or a small number of known body types. Conference room seating, theater seating and other group seating may be, with regard to comfort but not weight, similarly challenging as is airline passenger seating because individuals do not have the opportunity to choose a personalized seat. For this reason, while the explanation and description of the invention in this application relates specifically to optimizing the geometry of aircraft seats, the methods set out in this application also have application to seats of other types used in different venues.
Known membrane suspension seating design offers no mechanism for optimizing seating for the wide variety of body shapes present in the population, or to multiple postures. Accordingly, what is needed is a mechanism applicable to lightweight seat membranes, as well as a method to optimize a seat membrane for a commonly-encountered range of passengers and seating postures.